Atheras's Altered Firebolt

An orb of fire shoots toward a creature of your choice within range. Make a ranged spell attack against that target. On a hit, the target takes 2d8 fire damage, and it is set ablaze. The target takes an additional 1d8 fire damage at the end of their turn unless they or another creature use their action to extinguish the flame.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, both of the damages increases by 1d8 for each slot level above 1st.